i) Field of the Invention
The present invention relates to a carriage driving apparatus that drives a carriage of a printer or the like by a motor, and a motor control method for controlling the motor. The present invention more particularly relates to a carriage driving apparatus and a motor control method characterized by the determination of parameters used in the control of the motor.
ii) Description of the Prior Art
A conventional carriage of a printer or the like is connected to an endless belt driven by a motor, and is moved in a scanning direction by driving the endless belt through a pulley and the like in accordance with the rotation of the motor. To adjust the moving speed of the carriage to a desired value, the control of the motor is performed based on a variety of, parameters. For example, when the motor is controlled by so-called PID control, in which feedback control is performed using P control (Proportional control), I control (Integral control) and D control (Differential control) together, parameters such as P gain (Proportional gain), I gain (Integral gain) and D gain (Differential gain) are used.
When the apparatus temperature of a printer is low while driving a carriage, oil applied to the mechanism of the printer is hardened, resulting in a larger load to the motor than a load at normal temperature. Then, the apparatus temperature is detected by a sensor, and the control amount is determined in accordance with the detected temperature (see Publication of Unexamined Japanese Patent Application No. 7-163182).
The load applied to the motor for driving the carriage varies also depending on the assembly error or variation present among individual apparatuses such as printers. Conventionally, there is no effective measures to eliminate the influence of such variation in the load among individual apparatuses, which results in variation in the control accuracy among individual apparatuses such as printers.
Therefore, an object of the present invention is to provide a carriage driving apparatus that drives a carriage of a printer or the like by a motor, and a motor control method for controlling a motor, according to which variation in the control accuracy among apparatuses can be substantially eliminated.